Sunday, April 17, 2011

The sobering
reality set in on Saturday afternoon when Joe Nathan blew his second save
opportunity in as many tries, forcing Ron Gardenhire to strip him of the team’s
ceremonial position of closer.

Overall, the numbers
resembled nothing from his pre-surgery performance. Whereas pre-Tommy John
Nathan was one of the game’s best relievers, demonstrating a well-balanced repertoire
of equal parts precision and power, the post-op Nathan has failed to get ahead
of hitters, unable to get them to chase much out of the strike zone and miss
any bats:

First-Pitch Strike%

Contract%

Chase%

Swinging Strike%

2008

63.6

70.0

30.3

14.0

2009

63.8

68.7

32.9

14.8

2011

48.2

90.7

20.3

4.6

This led to
an increase in walks, hits, base-runners, Johnny Damon-walk-offs-and-celebrating–in-only-the-douchebaggery-way-he-can and disappointment among the coaching
staff when Nathan has been unable to solidify a Twins victory.

Despite
issues with his ability to command all pitches across the board, according to Tom
Pelissero of 1500ESPN, Gardenhire attributed most of Nathan’s reduction in
whiffs to the lack of bite on his slider, his once-premier pitch:

"It's that slider that's not snapping like it was, and that's
the one he used to get people to swing and miss at an awful lot. Now he's kind
of gone to a little bit of a curveball, because his slider is still not there
yet. And that's probably par for the course with the elbow thing like that."

“According to Inside Edge's data, from 2007 to 2009, opponents
managed to hit just .163/.205/.234 (AVG/OBP/SLG) off of his slider. Twins
infielders would regularly get a quick breeze in their directions as opponents swung-and-missed
a whopping 40.8 percent of the time when taking a cut. For Nathan, his slider
was his go-to out-pitch racking up 122 of his 242 strikeouts on it. When
hitters did make contact, the slider was typically kept on the ground – a stark
contrast to his fastball which they tended to elevate.”

Comparatively, while only throwing a couple of handfuls of
sliders this season, the results on the pitch have been atrocious:

Joe Nathan’s slider performance

Well-Hit Avg.

In Play%

Chase%

Miss%

2009

.138

26.0

45.0

44.0

2011

.443

60.0

11.0

10.0

League Avg

.131

36.4

30.5

31.0

(MyInsideEdge.com)

There are
some schools of thought that suggest a bad slider is worse than almost any
other type of bad pitch. According to an article from The
Sporting News dated back in 1994 (is it still okay to cite something written when Ace of Base was topping the charts?) discussing the topic, where a hanging curveball
has the advantage of having a gap in velocity, a bad slider is thrown on the same
plane as a fastball and comes in at near-identical velocity. In Nathan’s case,
where the ’09 slider had a six mile per hour differential from the fastball, since
then just three miles per hour separate his slider from his fastball.

Using pitch
f/x we see two realities of Nathan’s pre-Tommy John and post-Tommy John
sliders. The first is that, on average, his slider isn’t finishing down in the
zone as it did in the past. According to data found at pitchfx.texasleaguers.com,
Nathan’s movement on his slider isn’t witnessing the same amount of vertical
spin as it did in the past:

Joe Nathan’s slider movement

Vertical

Hortizonal

2009

2.29

1.17

2011

4.43

1.79

To better
understand those numbers, the first column represents a measurement in inches
of how much, on average, the pitch moves downward. More simply: the lower the
number, the greater the drop. The second column represents the east-west
movement. As the numbers increase away from zero and the negative numbers, this
means the pitch is moving towards the pitcher’s left – or in at a left-handed
batter. Knowing this, we can glean that Nathan’s slider has reminded up in the
zone more frequently this year thereby confirming Gardenhire’s statement regarding
a lack of bite. In essence, his 2011 slider is remaining closer to the same vertical
plane as his fastball.

The second thing
that pitch f/x data shows us is that, on average, Nathan’s release point on his
slider has sank somewhat:

This
lil’ factoid is likely the root cause of Nathan’s loss of vertical movement.

What
this shows us is that in 2009, Nathan demonstrated a greater ability to stay on
top of the baseball when chucking his slider. By staying on top, he was able to
gain downward movement rather than an increase in horizontal deflection. This season
- possibly because of the extended time off or simply because of the re-built
elbow - Nathan’s slider release point has been lower compared to his ’09 outings
and with it his slider has remained up in the zone.

Without
question, it is easier said than done telling someone to stay on top of a pitch
– particularly when there are physical influences such as a new elbow factored
in. However, while demoted down the ranks of the bullpen and consuming low
leverage innings, in those outings Nathan should be very conscious of where he
is releasing his slider and attempt to rediscover that release point.

About OtB

"Parker Hageman is the Michael Cuddyer of Twins bloggers -- not the flashiest guy out there, but a solid everyday player. Hageman produces spot-on analysis ... relying on in-depth stats and lots of charts. He takes a sober, performance-based view of players, letting others fall for a player's heart or his leadership skills in the clubhouse. Hageman is one of the four pillars holding up the Star Tribune's TwinsCentric blog."